This invention relates to a ventilation system for an automotive engine and more particularly to an improved engine arrangement that permits the use of a tuned induction system and a conveniently positioned crankcase ventilation system and oil separator therefor.
As is well known, the induction system for an internal combustion engine is very important in determining the performance of the engine. Recently it has been acknowledged that the performance of the engine, at least under some running conditions, can be improved by providing a relatively long intake runners that serve the individual ports of the engine. However, in many automotive applications the use of such long runners can give rise to certain problems.
Obviously, the engine compartment of motor vehicles is quite compact. Therefore, the provision of an intake system for the engine having long runners can be difficult to position within the engine compartment. One way that long runners can be achieved is by having the manifold double back over the top or cylinder head of the engine from the intake port and extend toward the other side of the engine. However, where the engine has overhead valves and overhead camshafts, the positioning of the intake manifold over the cylinder head can give rise to spatial problems. In addition, such an orientation can adversely effect the hood line of the vehicle. Since it is important to provide a low hood line for both aerodynamic and styling purposes, it must be insured that the height of the engine is not too great.
Furthermore, all engines employ a crankcase ventilating system for causing ventilating air to flow through the internal portions of the engine and particularly over the oil in the crankcase and through the cam chamber of the cylinder head. It is normally the practice to employ some form of oil separator to separate lubricant from the circulated air so that the lubricant will not be discharged to the atmosphere. In addition, if the lubricant is not removed from the circulating air, the quantity of oil in the lubricating system can become depleted.
With many types of engines, particularly those of the in line type, it has been the practice to position the oil separator in the cam cover of the engine. Of course, the oil separator must have a certain volume to operate effectively. If the intake system passes over the cylinder head and oil separator, then the height of the engine can be significantly increased.
It is, therefore, a principal object of this invention to provide an improved oil separator and manifold arrangement for an internal combustion engine that permits a low overall height without sacrificing any of the functional aspects of the engine.
It is a further object of this invention to provide an improved engine construction wherein an oil separator can be positioned in the head assembly of the engine, the intake manifold can pass at least in part over the oil separator and the engine nevertheless has a low overall height.